Before you start, disable your screen saver and all other applications that might be running.  (Look for small icons by the clock in the bottom right hand side of your screen.  They are programs currently running in memory.  Norton utilities is a common icon that you will see here.)

Run your anti-virus program and scan for viruses.  (If you don't have one, from a company like Norton or McAfee.)

Run Scandisk located at: Start-> Programs-> Accessories-> System Tools-> Scandisk.  Run the thorough test and select the Automatically fix errors check box.

Run Disk Defragmenter located at: Start-> Programs-> Accessories-> System Tools->Disk Defragmenter.  Select your hard drive(s) and let it run.

Search for files that can be deleted.  You can use your find program located at Start->Find->Files or Folders.  Checksum files that that have names like chk.001, chk.002, can be delete.  You would search for files named chk.* and the find program would look for those files.  Files that end in .tmp can be deleted.  These are temporary file that windows and other programs make.  Some of these temporary files may be in use by Windows when you try to delete they so just skip the ones in use.  Search for files named *.tmp to find all temporary files.  Look for folders called tmp or temp.  Windows and other programs use these folders to store temporary files which can be deleted.  If you are unsure if a file can be deleted or not, just leave it.  Better safe that sorry.

Make sure you have at least 100 MB of free space on your hard drive.  Windows used this space periodically when memory becomes low.

Turn off MS Office tool bar and disable it from starting when you boot your computer.

If you are running Internet Explorer 4.0 or greater, turn off the active desktop.

If you don't have a lot of memory on your video card, set your colors used to 256 or less in your display settings.

Turn off or disable any items selected on the "Plus" tab of the display properties.

Turn off all screen savers.

Eliminate any unnecessary programs that stay in memory.  Look in the "Startup" folder for programs that automatically start and look for Icons that are next to your clock in the lower right hand side of the screen.